For those who have not heard already, there is an entirely new style of ESCs flooding onto the market called “BlHeli_S” ESCs. BlHeli_S refers to the firmware these ESCs run, which is an extension of BlHeli built to run on a microprocessor called the BusyBee.
The benefit these ESCs purport to give you is a hardware PWM controller. This style of controlling the motor has long been used in KISS ESCs and is the main factor behind the “smoothness” everyone raves about when talking about them.
The real underlying benefit, if you ask me, is the cost savings. The BusyBee MCU actually costs less than the microcontroller used on standard BlHeli ESCs, so in the near future we should be seeing cheaper ESCs on the market with better performance.
BlHeli_S ESCs on the Market
I have been waiting for LittleBee-priced BlHeli_S ESCs before I pulled the trigger. Not because I couldn’t afford a couple of extra bucks, but because I like to have all my quads run the same ESCs so I only have to buy one set of spares.
The earliest BlHeli_S ESCs were the Aikon SEFM and the EMax Lightning series, and cost $16-$18/pc. That was simply too much for me – I’m just too used to the fantastic performance of LittleBees at $11/pc.
In early June, a new ESC popped up called the Sunrise Cicada. It sold from a couple of vendors on eBay and Amazon for $14-$15. We were getting closer. Then, just a few weeks ago, Banggood called the “Racerstar” at the fantastic price of $10/pp. I immediately pulled the trigger on both the 20a and 30a variants.
It turns out these Racerstar ESCs are identical to the Cicadas. This is awesome news as the Cicadas are the only BlHeli_S ESCs that seem to be immune to motor desync problems pilots are experiencing on the other ESC variants. Noone has isolated the problem for sure yet, but some suspect a capacitance issue. Whatever it is, EMax actually recalled their Lightning ESCs because of it.
When I received the ESCs, I was happy to find that both the 20a and 30a variants are pretty close to the form factor of the 20a Littlebee. This not only means they are drop in replacements for all my quads, but they also will fit on the arms with no overlap.
As expected, installation was a breeze. Next came programming. There is not a lot of documentation on how to “talk” to these ESCs, but I was pleased to find that it was an absolute non-issue. The latest BlHeliSuite release automatically recognizes the ESCs and comes packaged with firmware for them. Passthrough works so absolutely no work was required. Just plug the quad in, set up the end points and motor direction, and go fly.
You will notice the advantage of hardware PWM as soon as you arm your quadcopter for the first time. It is *quiet*. Eerily so. Unfortunately, I have to say that that’s really where the noticeable differences end. Once you’re in the air, the ESC performs exactly like any other BlHeli ESC. This is more or less what I expected, but it was a little bit disappointing. It is worth noting that the increased motor smoothness and throttle should allow you to increase your P gain a bit, adding improved precision to your flying, but that will require additional tuning and is not likely to make a huge difference in the average pilots flying.
Should you upgrade?
Depends – probably not if you are looking for an upgrade. Your $40 (or more..) is simply better spent on other things. Check out our intermediate pilots article for some suggestions on that front. If you are building a new quad, though, I absolutely recommend these racer stars. From my limited experience thus far, they are just as good as my beloved Littlebees, at just as good a price, with slightly improved performance. Plus, that buttery smooth idle is just to die for.
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If you are new to the site and liked this article, consider checking out our ESC buyers guide – which discusses much more about multirotor ESCs.